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Sinew Mechanical Properties

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BowEd:
A person needs to fine tune the application of sinew to properly test what sinew can do.

avcase:
I will dig around for what I have regarding sinew properties. It is certainly possible to model the performance and characteristics of a horn-wood-sinew composite bow with decent accuracy.  The sinew and horn are strained quite high compared to wood. About 3% working strain. It breaks at much higher strain levels.  Often, to check my modeling technique, I measure an existing bow as best as I can to create a model, and then compare the model to the real bow.

Testing a model against a real bow doesn’t tell you if the materials were used optimally.  To do this, I often create samples and measure the properties of these materials myself. 

Alan

BowEd:
Thickness levels of components and width and length dimensions are something to model after from bow to bow for draw weight.Once a person has a few successful template bows it's a lot easier to gauge for future bows.It takes the guessing game out of the process then.

Jano:
Adam Karpowicz published these data of tensile modulus for sinew : 0,9 - 2,4 GPa in his book. He also mentioned this source, which I read and appreciate :
 
D.G.Hepworth J.P.Smith  - 2002 - The mechanical properties of composites manufactured from tendon fibres and pearl glue (animal glue)

Free citations from it : "Dry bovine lover leg tendon was found to have a mean tensile modulus of 2,41 GPa and mean strength of 180 MPa. The mean failure strain was 25,6%. Tendon/glue composites formed with wet fibres ( 5cm long in 15 cm sample length and 7mm sample width ) at a fibre volume fraction of 50% were found to have a mean tensile modulus of  2,32 GPa and mean strength of 100 MPa. The mean failure strain was 20,6%. Maximum energy absorption - 18 MJ/m3."

Another values I found are : 2,81 GPa - 2,9 GPa - 1,24 Gpa ...

I also did two ( not very exact ) tests of slim "lateral digital extensor" from deer lover leg tendon in pure elongation and one test of sinew/gelatine layer in three point bending test ( using dial gauge ) personally and got similar results in the range of 2,4 to 2,9 Gpa and maybe more for "prestrained" tendon. ( Please see :
https://atarn.fi/t/grooving-core-before-sinewing/120/15         and up. There is also some modeling in VirtualBow. )

Hope it helps.

blindarcher:
Thanks All!  Ed, your suggestion falls about modeling based on existing bows is a great one and that is exactly what I did.  To my surprise, I got real good correlation and was able to estimate effects of humidity and moisture content by exposure time and location (upper Midwest, dry arid Southwest).  The results seem very reasonable and compare with some of the findings in Ryan Gill's latest book.

Thanks all!

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